livepatch/ppc64: Support use func_descr for new_func

hulk inclusion
category: feature
bugzilla: 51924
CVE: NA

---------------------------

The ppc64 ABI V1 function pointer points to the function descriptor,
which we use in the sample demo.

        $cat /proc/kallsyms | grep  livepatch_cmdline_proc_show
        80000000000d4830 d livepatch_cmdline_proc_show  [livepatch_sample]      -=> func descr
        80000000000d40c0 t .livepatch_cmdline_proc_show [livepatch_sample]      -=> func addr

However, the livepatch module made by kpatch just passes the address of
the function to kernel(saved in func->new_func), so the kernel needs to
obtain the toc address and combine the function descriptors to implement
long jump.

Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
Reviewed-By: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: yangerkun <yangerkun@huawei.com>

Signed-off-by: Dong Kai <dongkai11@huawei.com>

Signed-off-by: Ye Weihua <yeweihua4@huawei.com>
Reviewed-by: Kuohai Xu <xukuohai@huawei.com>
Reviewed-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>